变形介质油藏非线性不稳定渗流特征研究  

Non-linear Unstable Seepage Flow in Stress-sensitive Reservoirs

作　　者：葛宏选 党海龙 解伟 王继超 

机构地区：[1]陕西延长石油(集团)有限责任公司研究院,陕西西安710069

出　　处：《非常规油气》2015年第3期50-57,共8页Unconventional Oil & Gas

摘　　要：深层低渗透油藏中,储层承受高温高压,在开发过程中储层部分或者全部会发生不可逆变形,再加上存在启动压力梯度,储层流体呈现非线性渗流特点,使得地层特征更加复杂,严重影响油田开发。渗流室内实验研究表明,非线性段可以用幂律关系进行描述。在考虑了启动压力梯度和变形介质存在的前提下,建立了非线性不稳定渗流数学模型,并且求出定产量和定井底流压条件下模型的解。模型的实例分析结果表明,随时间增加,动边界向外推移,推移速度越来越慢;当启动压力梯度和压力敏感系数都增大时,相同时间向外拓展半径越小,压力波传递速度和范围也越小。因此,开发此类油田,其开发特征必须区别于常规的线性—弹性油藏的开发特点;在实际生产中,应利用模型对不同类型油藏进行分析,总结开采特征,制订科学、合理的技术政策,提高油田最终采收率。Deep low-permeability reservoirs feature in high temperature and high pressure. So reservoir may be deformed partially and thoroughly during development, which thus affects dynamic features of oilfield development seriously. Further- more, starting pressure gradient leads to non-linear seepage flow of reservoir fluids, which makes formation features more complicated. Seepage flow lab study showed that non-linear interval could be described by the power law relation. Taking starting pressure gradient and deformable medium into account, in this paper, a mathematic model of non-linear seepage flow was established, and the solution of the model with constant yield and bottom-hole flowing pressure was acquired. Case analysis showed that the flowing boundary was pushed outward more and more slowly as time increased. When starting pressure gradient and pressure sensitivity coefficient increased, the expanding radius got smaller at the same time, and the pressure wave propagation velocity and range became smaller. Therefore, development feature of such oilfields have to vary from that of conventional linear-elastic reservoirs. In actual production, types should he used for analyzing different reser- voirs and concluding the characteristics of these reservoirs, so as to formulate scientific and reasonable techniques to en- hance ultimate recovery in oilfields.

关 键 词：变形介质 不稳定渗流 非线性 启动压力梯度 数学模型 

分 类 号：TE312[石油与天然气工程—油气田开发工程]